The cusp of Carabelli, or Carabelli's tubercle, or ''tuberculum anomale'' of Georg Carabelli is a small additional

cusp A cusp is the most pointed end of a curve. It often refers to cusp (anatomy), a pointed structure on a tooth. Cusp or CUSP may also refer to: Mathematics * Cusp (singularity), a singular point of a curve * Cusp catastrophe, a branch of bifurc ...

at the mesiopalatal line angle of

maxillary first molar The maxillary first molar is the human tooth located laterally (away from the midline of the face) from both the maxillary second premolars of the mouth but mesial (toward the midline of the face) from both maxillary second molars. The function ...

s. This extra cusp is usually found on the secondary maxillary first molars and is rarely seen on primary maxillary second molars even less likely on other molars. This cusp is entirely absent in some individuals and present in others in a variety of forms. In some cases, the cusp of Carabelli may rival the main cusps in size. Other related forms include ridges, pits, or furrows. This additional cusp was first described in 1842 by the Hungarian Georg Carabelli (Carabelli György), the court dentist of the

Austrian Austrian may refer to: * Austrians, someone from Austria or of Austrian descent ** Someone who is considered an Austrian citizen, see Austrian nationality law * Austrian German dialect * Something associated with the country Austria, for example: ...

Emperor Franz. The cusp of Carabelli is a heritable feature. Kraus (1951) proposed that

homozygosity Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. ...

of a gene is responsible for a pronounced tubercle, whereas the

heterozygote Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mo ...

shows slight grooves, pits, tubercles or bulge. Later studies showed that the development of this trait is affected by multiple genes. The cusp of Carabelli is most common among Europeans (75-85% of individuals) and rarest in Pacific Islands (35-45%), although no study is referenced here to back up that claim. Although it is sometimes referred to in textbooks as the Cusp of Carabelli, it is actually a

tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection ...

, as it is may be made only of enamel, and may not contain dentin but never has a root underneath. It is unlikely, but entirely possible for the cusp to have a pulp horn. If the cusp is large, approaching the size of a regular cusp, then it will typically be formed of dentin and enamel.

See also

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